Note: This bottom line focuses on edible types of cinnamon. It does not include Cinnamomum camphora, or the camphor tree, which may be lethal to humans in large doses, or Cinnamomum kotoense, which is an ornamental species.

Cinnamon has been used as a spice around the world for centuries. It has also been used for its possible healing benefits. It has been used to improve stomach health and gas prevention. The only two species that are approved as medicinal herbs in the genus Cinnamomum areCinnamomum zeylanicum and C. cassia. The bark is used as a spice and is called cinnamon bark.

There is a lack of evidence supporting the use of cinnamon for any medical condition.

Cinnamon has been studied for the treatment of type 2 diabetes. Although there are conflicting results, many trials suggest significant blood sugar-lowering effects. Cinnamon has been shown to be effective in improving both blood sugar and insulin metabolism.

Cinnamon is also believed to have anti-inflammatory, antibacterial, antifungal, and antioxidant benefits. Research is ongoing in terms of its possible use for cancer or severe viral infections.

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

GRADE *

Early study suggests that cinnamon may have anti-allergy benefits. A combination product containing cinnamon may reduce nasal allergy symptoms. More studies are needed before a firm conclusion may be made.

C

Cinnamon has been studied as an antioxidant. Dried cinnamon extract (Cinnulin PF®) has been shown to improve antioxidant status in overweight or obese people with abnormal blood sugar levels. Further study is needed before conclusions can be made.

C

Early study suggests that cinnamon may treat bacterial infections. However, more research is needed in this area.

C

Cinnamon oil has been studied for its possible benefits in fighting bacteria that cause bad breath. Sugar-sweetened cinnamon gum has been studied. More research is needed in this area.

C

Cinnamon has been studied for chest pain caused by a bacterial infection. Further study is needed before a firm conclusion may be made.

C

Early studies suggest that cinnamon may affect insulin and blood sugar levels. Benefits have been found in type 2 diabetics in terms of reduced blood sugar and cholesterol. However, results are inconsistent. More research is needed in this area.

C

Early research has found that a combination herbal eye drop (OphthaCare) may be useful in treating some eye disorders, such as pink eye or dry eye. Further study is needed.

C

Cinnamon has been studied for use in Helicobacter pylori infection. Cinnamon extract has been used alone and in combination with other agents. More studies are needed in this field.

C

Cassia oil sprays (Cinnamomum cassia) have been studied for dust mites. Early research suggests that cinnamon may be useful as an insect repellant. However, further research is required.

C

Cinnamon has been studied for its possible effects on bacteria that may cause irritable bowel syndrome. A combination of cinnamon quills, bilberry, slippery elm bark, and agrimony was found to have mixed benefits for this purpose. More research is needed on the effects of cinnamon alone.

C

Early study suggests that cinnamon may be useful in the treatment of lung cancer. However, more research is needed before a firm conclusion may be made.

C

Early study suggests that cinnamon may be useful in the treatment of metabolic syndrome in prediabetic people. However, one trial reported a lack of effect. More research is needed in this area.

C

A combination ointment containing cinnamon may have benefits for people with osteoarthritis. More research is needed on the possible effects of cinnamon alone for this condition.

C

Cinnamon has been studied for premature ejaculation in combination with eight other herbs. Further study is needed to determine any effect of cinnamon alone.

C

Cinnamon has been studied for use in yeast infection. Early study has found mixed results. Further research is needed to determine the effectiveness of cinnamon for this purpose.

C

* Key to grades

A: Strong scientific evidence for this useB: Good scientific evidence for this useC: Unclear scientific evidence for this useD: Fair scientific evidence for this use (it may not work)F: Strong scientific evidence against this use (it likley does not work)

Tradition / Theory
The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.

As an antioxidant, capsules containing 250 milligrams of an aqueous cinnamon extract (Cinnulin PF®) have been taken by mouth twice daily for 12 weeks.

To treat yeast infection, eight cinnamon candy lozenges have been taken by mouth daily for one week. A dose of 20-30 milliliters of a cinnamon solution (250 grams of cinnamon cooked in 2,000 milliliters of water) has been gargled 4-6 times a day.

To treat diabetes, 1-6 grams of cinnamon has been taken by mouth in 1-3 divided doses daily for 40 days to 16 weeks. Capsules containing 500-1,000 milligrams of cinnamon have been taken by mouth 2-3 times daily for up to 12 weeks. One capsule containing 333 milligrams of cinnamon extract has been taken by mouth three times daily for eight weeks. Aqueous cinnamon extract delivering three grams of cinnamon powder has been taken by mouth daily. A dose of one gram in the form of cinnamon capsules has been taken by mouth daily for 90 days. Fifteen capsules containing 400 milligrams of cinnamon has been taken by mouth. A dose of 74 grams of Cream of Wheat containing six grams of ground cinnamon (Swagger Foods) has been taken by mouth. A dose of 2-6 tablets of 60 milligrams of cinnamon extract has been taken by mouth before breakfast for three months. Two capsules (250 milligrams) of a water-soluble cinnamon extract (Cinnulin PF®) have been taken by mouth twice daily for 40 days. Doses of 0.25-6 grams of cinnamon or cinnamon extract have been taken by mouth 1-3 times daily for up to 16 weeks.

To treat bad breath, cinnamic aldehyde and flavoring chewing gum has been chewed for 20 minutes at 60 chews per minutes.

To treat a Helicobacter pylori infection, 80 milligrams of cinnamon extract has been taken by mouth daily for four weeks.

To treat metabolic syndrome, two capsules (250 milligrams) of a water-soluble cinnamon extract, Cinnulin PF®, have been taken by mouth twice daily. A total of three grams of powdered cinnamon (Schwartz, UK) has been taken by mouth with a high-fat meal, half before the meal and half after.

As an insect repellant, a cream containing five percent cassia oil and five grams of cassia oil has been applied to the skin for up to 120 minutes. Doses of 0.006-0.102 milligrams per centimeters squared of C. cassia bark-derived extract have been applied to the skin. Doses of 0.013-0.153 milligrams per centimeter squared of trans-cinnamaldehyde (CA) or cinnamyl alcohol (CL) have been applied to the skin. Doses of 0.006-0.102 milligrams per centimeter squared of C. cassia bark-derived methanol extract have been applied to the skin. Doses of 0.003-0.051 milligrams per centimeter squared of trans-cinnamaldehyde (CA) or cinnamyl alcohol (CL) have been applied to the skin for up to 40 minutes.

Children (under 18 years old)

There is no proven safe or effective dose for cinnamon in children.

Safety
The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Allergies

Avoid in people who are allergic or sensitive to cinnamon, its parts, members of the Lauraceae family, and Balsam of Peru. There may be cross-reactions in people who are allergic or sensitive to ketoprofen, birch or mugwort pollens, and celery.

Cinnamon is one of the 10 major food allergens.

Side Effects and Warnings

Cinnamon is likely safe when taken by mouth for up to six weeks in doses of up to six grams daily.

Cinnamon may interfere with the way the body processes certain drugs using the liver's "cytochrome P450" enzyme system. As a result, the levels of these drugs may be increased in the blood, and may cause increased effects or potentially serious adverse reactions. People using any medications should check the package insert, and speak with a qualified healthcare professional, including a pharmacist, about possible interactions.

Cinnamon may increase the risk of bleeding. Caution is advised in people with bleeding disorders or taking drugs that may increase the risk of bleeding. Dosing adjustments may be necessary.

Cinnamon may lower blood sugar levels. Caution is advised in people with diabetes or low blood sugar, and in those taking drugs, herbs, or supplements that affect blood sugar. Blood sugar levels may need to be monitored by a qualified healthcare professional, including a pharmacist, and medication adjustments may be necessary.

Use cautiously in people who have autoimmune diseases or those taking drugs that may affect the immune system.

Use cautiously in people who have liver damage or those taking drugs that may affect the liver.

Use cautiously in people who are taking drugs for abnormal heart rhythms. Cinnamon may cause abnormal heart rhythms.

Use cautiously in people who are at risk for seizures. Cinnamon may cause seizures.

Use cautiously in people who are taking cholesterol-lowering drugs. Cinnamon may lower cholesterol and triglyceride levels.

Use cautiously in people who take agents that may increase sensitivity to sunlight. Cinnamon may increase sun sensitivity.

Cinnamon may cause low blood pressure. Caution is advised in people taking drugs or herbs and supplements that lower blood pressure.

Avoid in people who are allergic or sensitive to cinnamon, its parts, members of the Lauraceae family, and Balsam of Peru. Avoid in large amounts (more than those found in foods).

Cinnamon may increase the risk of bleeding when taken with drugs that increase the risk of bleeding. Some examples include aspirin, anticoagulants ("blood thinners") such as warfarin (Coumadin®) or heparin, anti-platelet drugs such as clopidogrel (Plavix®), and non-steroidal anti-inflammatory drugs such as ibuprofen (Motrin®, Advil®) or naproxen (Naprosyn®, Aleve®).

Cinnamon may lower blood sugar levels. Caution is advised when using medications that may also lower blood sugar. People taking drugs for diabetes by mouth or insulin should be monitored closely by a qualified healthcare professional, including a pharmacist. Medication adjustments may be necessary.

Cinnamon may interfere with the way the body processes certain drugs using the liver's "cytochrome P450" enzyme system. As a result, the levels of these drugs may be increased in the blood, and may cause increased effects or potentially serious adverse reactions. People using any medications should check the package insert, and speak with a qualified healthcare professional, including a pharmacist, about possible interactions.

Cinnamon may increase the risk of bleeding when taken with herbs and supplements that are believed to increase the risk of bleeding. Multiple cases of bleeding have been reported with the use of Ginkgo biloba, and fewer cases with garlic and saw palmetto. Numerous other agents may theoretically increase the risk of bleeding, although this has not been proven in most cases.

Cinnamon may interfere with the way the body processes certain herbs or supplements using the liver's "cytochrome P450" enzyme system. As a result, the levels of other herbs or supplements may become too high in the blood. It may also alter the effects that other herbs or supplements possibly have on the P450 system.

Cinnamon may lower blood sugar levels. Caution is advised when using herbs or supplements that may also lower blood sugar. Blood glucose levels may require monitoring, and doses may need adjustment.

Cinnamon may cause low blood pressure. Caution is advised in people taking herbs or supplements that lower blood pressure.

Cinnamon may also interact with Alzheimer's herbs and supplements, anti-asthma herbs and supplements, antibacterials, anticancer herbs and supplements, antifungals, anti-gout herbs and supplements, anti-inflammatory herbs and supplements, anti-obesity herbs and supplements, antioxidants, anti-spasm herbs and supplements, antivirals, artemisia, cholesterol-lowering herbs and supplements, clove, ephedra, herbs and supplements that may affect the immune system, herbs and supplements that may affect the nervous system, herbs and supplements that may be harmful to the liver, herbs and supplements that may increase light sensitivity, herbs and supplements that may treat abnormal heart rhythms, herbs and supplements that may affect the stomach, insect repellants, pain relievers, phytoestrogens, sympathomimetic herbs and supplements, and vitamin E.

The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.